Exocytosis of D-Aspartate from INS-1E Clonal .BETA. Cells

Iharada, Masafumi; Hiasa, Miki; Kobara, Ayumi; Moriyama, Yoshinori

doi:10.1248/bpb.30.1329

Cited by 9 publications

(6 citation statements)

References 18 publications

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“…In the adult rat pancreas, d-Asp immunoreactivity is predominantly observed in the Langerhans islet [43], with a D% of approx. 8% [44]. The Langerhans islet comprises at least four major types of endocrine cells: glucagon-secreting ␣ cells, insulinsecreting ␤ cells, somatostatin-secreting ␦ cells, and pancreatic polypeptide-secreting PP cells.…”

Section: Expression and Localization Of D-asp In Mammalian Tissues Anmentioning

confidence: 99%

d-Aspartate—An important bioactive substance in mammals: A review from an analytical and biological point of view

Katane

Homma

2011

Journal of Chromatography B

113

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Section: Expression and Localization Of D-asp In Mammalian Tissues Anmentioning

confidence: 99%

d-Aspartate—An important bioactive substance in mammals: A review from an analytical and biological point of view

Katane

Homma

2011

Journal of Chromatography B

113

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“…On the other hand, the extracellular levels of d -Asp, which is localized in alpha cells and acts on the glutamate site (GluN2) of NMDAR, remained consistent, despite the increase in glucose levels (Figure A,B). Although d -Asp has been found in beta cells at low amounts, most d -Asp is located in glucagon-secreting alpha cells. , Glucagon release is inhibited by the increase of extracellular glucose and insulin levels . This again suggests that d -Asp is stored/released in a distinct manner than glucagon.…”

Section: Discussionmentioning

confidence: 99%

“…Although d -Asp has been found in beta cells at low amounts, most d -Asp is located in glucagon-secreting alpha cells. 8 , 46 Glucagon release is inhibited by the increase of extracellular glucose and insulin levels. 47 This again suggests that d -Asp is stored/released in a distinct manner than glucagon.…”

Section: Discussionmentioning

confidence: 99%

Relations between Glucose and d-Amino Acids in the Modulation of Biochemical and Functional Properties of Rodent Islets of Langerhans

Lee,

Wei

et al. 2023

ACS Omega

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The cell-to-cell signaling role of d -amino acids ( d -AAs) in the mammalian endocrine system, particularly in the islets of Langerhans, has drawn growing interest for their potential involvement in modulating glucose metabolism. Previous studies found colocalization of serine racemase [produces d -serine ( d -Ser)] and d -alanine ( d -Ala) within insulin-secreting beta cells and d -aspartate ( d -Asp) within glucagon-secreting alpha cells. Expressed in the islets, functional N -methyl- d -aspartate receptors are involved in the modulation of glucose-stimulated insulin secretion and have binding sites for several d -AAs. However, knowledge of the regulation of d -AA levels in the islets during glucose stimulation as well as the response of islets to different levels of extracellular d -AAs is limited. In this study, we determined the intracellular and extracellular levels of d -Ser, d -Ala, and d -Asp in cultures of isolated rodent islets exposed to different levels of extracellular glucose. We found that the intracellular levels of the enantiomers demonstrated large variability and, in general, were not affected by extracellular glucose levels. However, significantly lower levels of extracellular d -Ser and d -Ala were observed in the islet media supplemented with 20 mM concentration of glucose compared to the control condition utilizing 3 mM glucose. Glucose-induced oscillations of intracellular free calcium concentration ([Ca 2+ ] i ), a proxy for insulin secretion, were modulated by the exogenous application of d -Ser and d -Ala but not by their l -stereoisomers. Our results provide new insights into the roles of d -AAs in the biochemistry and function of pancreatic islets.

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“…Hyperglycemia can induce the release of D-Asp from the retina of diabetic rats and is related to diabetic retinopathy ( 58 ). Although D-Asp is found in α cells and can be released from the rat insulinoma cell line INS-1 along with insulin ( 59 , 60 ), the function of D-Asp in islets is unclear.…”

Section: Amino Acidsmentioning

confidence: 99%

Potential Therapeutic Targeting Neurotransmitter Receptors in Diabetes

2022

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Neurotransmitters are signaling molecules secreted by neurons to coordinate communication and proper function among different sections in the central neural system (CNS) by binding with different receptors. Some neurotransmitters as well as their receptors are found in pancreatic islets and are involved in the regulation of glucose homeostasis. Neurotransmitters can act with their receptors in pancreatic islets to stimulate or inhibit the secretion of insulin (β cell), glucagon (α cell) or somatostatin (δ cell). Neurotransmitter receptors are either G-protein coupled receptors or ligand-gated channels, their effects on blood glucose are mainly decided by the number and location of them in islets. Dysfunction of neurotransmitters receptors in islets is involved in the development of β cell dysfunction and type 2 diabetes (T2D).Therapies targeting different transmitter systems have great potential in the prevention and treatment of T2D and other metabolic diseases.

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Exocytosis of D-Aspartate from INS-1E Clonal .BETA. Cells

Cited by 9 publications

References 18 publications

d-Aspartate—An important bioactive substance in mammals: A review from an analytical and biological point of view

d-Aspartate—An important bioactive substance in mammals: A review from an analytical and biological point of view

Relations between Glucose and d-Amino Acids in the Modulation of Biochemical and Functional Properties of Rodent Islets of Langerhans

Potential Therapeutic Targeting Neurotransmitter Receptors in Diabetes

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